Time adjustment apparatus for digital clock

ABSTRACT

Apparatus for making time adjustments or corrections in a digital clock having a plurality of time-indicating driven elements, one of which indicates the least time unit in the clock, for example, seconds. A pawl lever having a pawl for engaging a stop on the driven seconds wheel for indicating the least time units is manually actuated to stop this seconds wheel after a correct time has been set in the hours, tens of minutes and minutes time-indicating wheels. Upon release of the seconds wheel, the time is correctly and accurately set in the clock including correct time as to the least time unit. The seconds wheel is stopped by engaging it and using its force of rotation to disengage an input drive element therefrom or to open a switch disenabling a drive motor. The pawl lever is released at the time of a time signal. The seconds wheel is releasably held at a given position of rotation thereof corresponding to a given time indication when making the time correction or setting.

United States Patent Kitai et al.

[ Mar. 19, 1974 TIME ADJUSTMENT APPARATUS FOR DIGITAL CLOCK [75] Inventors: Kitoshi Kitai, Tokyo; Mitsuo Koyama, Yotsukaido; Shogo Kato, Kichioka; Yozuru Takazawa, Tokyo; Shinji Nagaoka, Yotsukaido, all of Japan [73] Assignee: Seiko Koki Kabushiki Kaisha,

Tokyo, Japan [22] Filed: Nov. 13, 1972 21 Appl. No.: 305,689 g [30] 7 Foreign Application Priority Data Nov. 19, 1971 Japan .4692911 [52] US. Cl. 58/855, 58/125 C [51] Int. Cl. G04b 27/00, G04b 19/02 [58] Field of Search 58/34-37, 85.5,

[56] References Cited UNITED STATES PATENTS 2.65l,l67 9/1953 Benson 58/[25 C Primary ExaminerGeorge H. Miller, Attorney, Agent, or FirmRobert E. Burns; Emmanuel J. Lobato 57 ABSTRACT Apparatus for making time adjustments or corrections in a digital clock having a plurality of time-indicating driven elements, one of which indicates the least time unit in the clock, for example, seconds. A pawl lever having a pawl for engaging a stop on the driven seconds wheel for indicating the least time units is manually actuated to stop this seconds wheel after a correct time has been set in the hours, tens of minutes and minutes time-indicating wheels. Upon release of the seconds wheel, the time is correctly and accurately set in the clock including correct time as to the least time unit. The seconds wheel is stopped by engaging it and using its force of rotation to disengage an input drive element therefrom or to open a switch disenabling a drive motor. The pawl lever is released at the time of a time signal. The seconds wheel is releasably held at a given position of rotation thereof corresponding to a given time indication when making the time correction or setting.

3 Claims, 3 Drawing fi u'ies TIME ADJUSTMENT APPARATUS FOR DIGITAL CLOCK BACKGROUND OF THE INVENTION This invention relates generally to digital clocks and more particularly to an apparatus for setting and adjusting time in a digital clock.

In conventional time-adjusting or time-correcting apparatus for digital clocks, the time corrections are introduced into the clock by adjusting the hour indication wheel, a tens of minutes indication wheel, and a minute indication wheel to correct the time by revolving a knob. For example, when the correct time is 1 1:59, the digital clock is adjusted to show 11 on the hour time-indicating element of the wheel, and 59 in the two minute-indicating wheels.

Since the time setting is not made with respect to the least time unit wheel, which is the unit of seconds, the setting as to the seconds is left uncertain. The uncertainty depends upon the position of the seconds unit wheel and in a worst case, a potential error of nearly plus or minus one minute may exist in the time setting. In order to avoid this type of error, it is, or would be, necessary for interrupting drive or power to the digital clock at the time when the real time corresponds to the time set. That is to say, the clock is set in the hour and minutes settings, and then power or drive is interrupted and the clock restarted at the exact time corresponding to the minutes setting, and when the seconds setting is at a zero setting. However, this mode of operation, interrupting power, is impossible where the digital clock is built into a television set or some other device where the power cannot be interrupted, because a digital clock is electrically connected with the television set or other apparatus in a single circuit.

SUMMARY OF THE INVENTION It is a principal object of the present invention to provide an accurate and simple apparatus for setting and adjusting time in a digital clock.

In accordance with the invention, the apparatus for setting and adjusting the time is part of a digital clock that has a plurality of time-indicating driven elements, such as wheels, which are scttable to desired time indications. One of the elements comprises a least time unit element, for example, a seconds unit time-indicating wheel. The apparatus comprises means to selectively stop the least time unit time-indicating element in a position corresponding to a selected time indication. When this element is released, it is released when the real time corresponds to the time set on the time indicating element.

The apparatus is constructed in a first embodiment in which a detecting or sensing wheel or cam is driven in conjunction with the seconds indicating wheel, and is provided with a projection on a side thereof which is engaged by a pawl on a pawl lever selectively actuated manually to stop the rotation of the seconds indicating wheel at a selected point of rotation or position. Since the hours and minutes wheels have been set, the stopping of the seconds wheel allows for releasing it for to tation when the real time corresponds with the hours and minutes introduced and whatever setting has been established on the seconds wheel. The release is accomplished by releasing the pawl lever, which is restored to a disengaged position.

In another embodiment, the pawl lever is provided with a pawl on a slidable element that has an arm which normally keeps closed an electrical circuit that energizes the driving of the seconds-indicating or seconds wheel. When the pawl is engaged with the seconds wheel for stopping it, the slidable element is activated to a position in which it disenables the electrical circuit so that the electrical drive for the wheel is de-energized and the seconds wheel is stopped. When the pawl lever is manually restored to its rest position, the pawl slidable element is automatically restored by a biasing spring to a position in which it closes the circuit and the seconds wheel is again driven.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary, diagrammatic side elevation view of a digital clock provided with an apparatus according to the invention;

FIG. 2 is a fragmentary, diagrammatic front elevation view of a digital clock of the type disclosed in FIG. 1 provided with another embodiment of an apparatus according to the invention, and

FIG. 3 is a fragmentary, diagrammatic side elevation view of a digital clock provided with a third embodiment of the apparatus according to the invention.

Other objects and advantages will appear from the following description of an example of the invention, and the novel features will be particularly pointed out in the appended claims.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In accordance with the drawings, and more particularly FIGS. 1 and 2, digital clocks, provided with the invention, shown fragmentarily in the drawings comprise a plurality of time-indicating driven elements, such as time-indicating wheels, for setting the hour, tens of minutes, minutes, and a fourth wheel for setting seconds. A toothed wheel or position detector gear 2 is secured on a shaft 3 in conjunction with the other timeindicating units for rotation synchronously with the seconds wheel 1 and is driven by a rotationally driven drive gear 4 rotatable on a shaft 5 and provided with a bearing having a longitudinal slot 6 as diagrammatically illustrated. The gear wheel 2 is provided with a projection 7 on a major surface or side surface thereon for stopping the rotation of the seconds wheel as hereinafter described.

A pawl lever 8 provided with a pawl 9 and pivotally mounted on a pivot 10 is normally biased into engagement with a fixed stop 1 1 by a spring 12. When it is desired to make a time correction or time adjustment in the digital clock, the hours and minutes wheels are set to the desired time in a conventional manner for digital clocks by means not shown. The seconds wheel is then temporarily stopped by actuating the lever 8 to a raised position, illustrated in broken lines in FIG. 1, so that the pawl 9 is placed in the path of travel of the projection 7, which abuts thereagainst, illustrated in broken lines and the seconds wheel 1 is stopped. The gear drive 4 continues to be driven and meets resistance of the stopped gear 2 and tends to disengage itself from the gear 3 in view of the slotted or elongated bearing 6. The drive input gear 4 moves or backs away to a position illustrated in broken lines in FIG. 1, in which it is disengaged from the gear 2, which drives the seconds wheel 1, sufi'iciently to stop driving the gear 2.

While the seconds wheel is being stationarily held, a time signal may indicate the real time, for example, an audible signal on a radio, or a video signal or audio signal in a television set. It is received so that the operator releases the lever 8, since presumably the time standard signal corresponds to the real time, which is the time desired to be set into the digital clock.

Upon release of the pawl lever 8, the restoring or biasing spring 12 restores the lever and pawl 9 to the position illustrated in solid lines, so that the position detector gear 2 is free to rotate and the input drive gear 4 again fully engages or couples itself to the drive gear 2, and drive is again imparted to the seconds Wheel, so that the accurate time has been set in the digital clock.

A second embodiment of the invention as illustrated in FIG. 2, in which reference numerals applied to the component parts thereof correspond to those of FIG. 1, wherever the component parts of the two embodiments correspond. In this instance, the drive input wheel 4 may be either a gear or a friction wheel. For purposes of this description, it is assumed that the drive input wheel 4 is a friction wheel. In this embodiment, a second friction wheel 4 drives an input wheel associated with the minute wheel wherein the time setting illustrated in FIG. 2 is that of three minutes. This second wheel is likewise provided with a projection, not shown, which is engaged by a pawl lever 13 when a pawl lever 8 is actuated for stopping the minutes wheel 1. In this instance, both levers are connected through a connecting lever 14, provided with a knob 15 for manual actuation of the two pawl levers simultaneously as required for stopping the seconds and minutes wheels. When these two wheels are stopped and held, the friction drive wheels 4, 4 will not drive them and upon release of the knob 15, the two time-indicating wheels are released at a time corresponding to the real time which has been set into the clock.

The minute wheel has indicia thereon and it is stopped when a marker 16 begins to show through a viewing window as shown. In each of the embodiments, the time-indicating wheel stopped is detected as to its position and its stopping position is at a preferable position or time indication, for example, at zero seconds. This permits exact setting of the time in the clock to correspond with the real time signal or time standard signal.

A third embodiment of the digital clock provided with an apparatus according to the invention is illustrated in FIG. 3. In this instance, the reference numerals corresponding to those of FIG. 1 are likewise employed. However, in this instance, the pawl 9 is constructed as an arm of a slidable lever 17 mounted on the pawl lever 8. This slidable pawl has an elongated slot 18 within which are received two axially spaced pins 20, 21 mounted on the pawl lever 8. The pawl slidable element 17 has a second arm 19 and is biased by a spring 22 secured at one end thereof to the slidable pawl 17 and its other end to the pawl lever 8 biasing the second arm 19 toward the right in the drawing. The second arm 19 is provided with an insulator tip 23 that cooperates with a switch 24 for normally maintaining it closed.

The switch comprises two resilient, flexible contacts 25, 26. One contact 25 is biased toward the left, as illustrated in both lines, so that if it were not for the pressure applied by the second arm of the pawl lever in the position illustrated in solid lines, the switch would open. The pawl slider 17 is biased towards the right by its spring, and the tip 23 maintains the switch closed. The switch 24 is part of a circuit by which a motor 27 is driven by power provided through a plug 28. The motor 27 drives the friction wheel 4 rotatable on the shaft 5 through drive elements not shown.

When a given time is to be set in the digital clock, in FIG. 3, the hour and tens of minutes and minute wheels are set as before described. This setting is made in anticipation of the real time indication with which the digital clock is going to be made to correspond. Preliminary to receipt of this real time signal or indication, the pawl lever 8 is lifted manually to the position illustrated in broken lines and the pawl 9 is placed in the path of a projection or pin 7' on the drive wheel 2, so that when it engages the pawl, the drive wheel 2 is stopped after the pawl lever 17 has been moved toward the left against the action of its spring and the pin 20 has limited its axial travel. In this position, the second arm 19 is moved to the position illustrated in broken lines, so that the switch 24 is allowed to open. The motor 27 is thus de-energized and the input drive wheel stops, as well as the time-indicating seconds wheel 1.

When the real time standard signal which corresponds with the time set into the clock is received visibly or audibly, the pawl lever 8 is released and the biasing spring 12 restores it to the position shown in solid lines, in which case the pawl 9 is disengaged from the stop 7 and the spring 22 draws the pawl slider 17 toward the right, so that its axial travel is limited by the pin 21. In moving towards the right, the slider 17 carries its second arm 19 with it so that the insulative tip 23 presses against the contact 25 of the switch 24, which is then closed. The motor 27 is thus electrically energized so that the input wheel 4 receives drive and the seconds wheel 1 is then again driven for normal operation.

Those skilled in the art will see that the apparatus comprising the invention makes it possible to eliminate errors in time, corrections or adjustments in a conventional digital clock. Moreover, the invention requires adding only a few parts to conventional digital clocks for carrying out the mode of operation as above described.

What we claim and desire to secure by Letters Patent 1. Apparatus for making time adjustments in a digital clock, said clock comprising a plurality of timeindicating driven wheels, one of said driven wheels comprising a least time unit driven wheel, means for driving said driven'wheel' comprising an electrical circuit having a drive motor for driving said driven wheel,

means for selectively stopping the least unit time indicating driven wheel in a position corresponding to a selected time indication comprising means cooperative with said driven wheel for opening said electrical circuit thereby stopping said drive motor, and means to release said least time unit driven wheel when real time corresponds to the time set on said time indicating driven wheels.

2. Apparatus for making time adjustments in a digital clock, said clock comprising a plurality of timeindicating driven wheels one of said driven wheels comprising a least time unit driven wheel, means for driving said driven wheel comprising an electrical circuit having a drive motor for driving said driven wheel, stop on said driven wheel, a manually operated pawl clock according to claim 2, in which said electrical circuit comprises a normally closed switch, and in which said pawl comprises means opening said switch when said pawl engages said stop, and means in said switch closing said switch when said pawl is disengaged from said stop. 

1. Apparatus for making time adjustments in a digital clock, said clock comprising a plurality of time-indicating driven wheels, one of said driven wheels comprising a least time unit driven wheel, means for driving said driven wheel comprising an electrical circuit having a drive motor for driving said driven wheel, means for selectively stopping the least unit time indicating driven wheel in a position corresponding to a selected time indication comprising means cooperative with said driven wheel for opening said electrical circuit thereby stopping said drive motor, and means to release said least time unit driven wheel when real time corresponds to the time set on said time indicating driven wheels.
 2. Apparatus for making time adjustments in a digital clock, said clock comprising a plurality of time-indicating driven wheels one of said driven wheels comprising a least time unit driven wheel, means for driving said driven wheel comprising an electrical circuit having a drive motor for driving said driven wheel, stop on said driven wheel, a manually operated pawl lever having a pawl positionable in a position for engaging said stop and stopping said least time unit driven wheel after a corrected time has been set in the other time-indicating driven wheels, and means for disengaging said pawl from said stop when real time corresponds to the time set on said time-indicating driven wheels.
 3. Apparatus for making time adjustments in a digital clock according to claim 2, in which said electrical circuit comprises a normally closed switch, and in which said pawl comprises means opening said switch when said pawl engages said stop, and means in said switch closing said switch when said pawl is disengaged from said stop. 